1. Field of the Invention
The present invention relates to a substrate processing apparatus and a maintenance method therefor, and particularly to a semiconductor device manufacturing apparatus and a maintenance method therefor wherein a semiconductor wafer is handled as a substrate.
2. Description of the Related Art
A semiconductor device manufacturing apparatus includes, for example, a reaction furnace, a boat for holding a large number of wafers, a boat elevator for inserting and retrieving the boat into and from the reaction furnace, a cassette shelf for accommodating wafer cassettes in which the wafers are placed, a wafer transfer device for transferring the wafers between the boat and the cassette, a cassette stage for delivering and receiving the wafer cassettes to and from the outside of the semiconductor device manufacturing apparatus, and a cassette transfer device for transferring the cassettes between the cassette stage and the cassette shelf.
In the above described semiconductor device manufacturing apparatus, the maintenance is performed from the three directions, i.e., from the front face, the back face and one of the side faces, and therefore a space for maintenance must be secured around the semiconductor device manufacturing apparatus, and a large space is required for installing the apparatus, and it is uneconomical.